4AIN
Crystal structure of BetP with asymmetric protomers.
Summary for 4AIN
| Entry DOI | 10.2210/pdb4ain/pdb |
| Related | 2WIT |
| Descriptor | GLYCINE BETAINE TRANSPORTER BETP, SODIUM ION, TRIMETHYL GLYCINE, ... (8 entities in total) |
| Functional Keywords | membrane protein, chemosensor and osmosensor, secondary transporter, sodium coupled transport, transmembrane, hyperosmotic stress |
| Biological source | CORYNEBACTERIUM GLUTAMICUM |
| Cellular location | Cell membrane; Multi-pass membrane protein: P54582 |
| Total number of polymer chains | 3 |
| Total formula weight | 175466.84 |
| Authors | Koshy, C.,Ziegler, C.,Yildiz, O. (deposition date: 2012-02-10, release date: 2012-06-06, Last modification date: 2023-11-15) |
| Primary citation | Perez, C.,Koshy, C.,Yildiz, O.,Ziegler, C. Alternating-Access Mechanism in Conformationally Asymmetric Trimers of the Betaine Transporter Betp. Nature, 490:126-, 2012 Cited by PubMed Abstract: Betaine and Na(+) symport has been extensively studied in the osmotically regulated transporter BetP from Corynebacterium glutamicum, a member of the betaine/choline/carnitine transporter family, which shares the conserved LeuT-like fold of two inverted structural repeats. BetP adjusts its transport activity by sensing the cytoplasmic K(+) concentration as a measure for hyperosmotic stress via the osmosensing carboxy-terminal domain. BetP needs to be in a trimeric state for communication between individual protomers through several intratrimeric interaction sites. Recently, crystal structures of inward-facing BetP trimers have contributed to our understanding of activity regulation on a molecular level. Here we report new crystal structures, which reveal two conformationally asymmetric BetP trimers, capturing among them three distinct transport states. We observe a total of four new conformations at once: an outward-open apo and an outward-occluded apo state, and two closed transition states--one in complex with betaine and one substrate-free. On the basis of these new structures, we identified local and global conformational changes in BetP that underlie the molecular transport mechanism, which partially resemble structural changes observed in other sodium-coupled LeuT-like fold transporters, but show differences we attribute to the osmolytic nature of betaine, the exclusive substrate specificity and the regulatory properties of BetP. PubMed: 22940865DOI: 10.1038/NATURE11403 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (3.1 Å) |
Structure validation
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